Fire arm



G, E. MUNSON Jan. 3, 1939.

, FIRE ARM Filed June 21, 1 57 2 Sheets-Sheet 1 v E g-F (Ittomeg G. E. MUNSON Jan. 3, 1939.

FIRE ARM 2 Sheets-Sheet 2 Filed June 21, 1937 3nventor- (Ittorneg Patented Jan. 3, 1939 UNE ETEE STATES E ATEZN E @FFEQE 6 Claims.

My invention relates to improvements in fire arms for overcoming the erratic firing conditions existing and to provide a uniform placement and clamping of the cartridge at the time of firing to insure greater accuracy on the target.

An important object of the invention is to provide a head space take-up operating automatically upon the cartridge case to hold the cartridge firmly under pressure between the bolt and the barrel when the bolt is in place.

A further object of the invention is to provide a floating or longitudinally movable barrel slidably mounted in a sleeve to insure uniformi 1 of firing conditions of cartridges that vary in rim 5 thickness.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part 9 of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure l is a side view of a standard rifle of small caliber using rim fire cartridges with parts 5 broken away to disclose the features of my invention,

Figure 2 is a perspective view of a spring utilized in connection with the said invention,

Figure 3 is a cross section taken on the line 3-3 of Figure 5,

Figure 4 is a fragmentary, cross sectional view through a portion of a rifle disclosing the invention, and

Figure 5 is an enlarged fragmentary, longitudinal cross sectional View through the portion of a rifle disclosing certain features of assembly of my invention.

In the drawings wherein for the purpose of illustration is shown a preferred embodiment of to my invention, the numeral i5 designates as a whole a rifle of the type commonly used for target practice, said rifle being of the small bore type utilizing rim fire ammunition. The rifle includes the usual barrel l l, stock 12, with stockpiece or forearm 13 extending well forward of the barrel. The usual rifle barrel is secured into a receiver M by threading the butt end of the barrel into the receiver. I deviate from this prac- 5 tice in that I provide in my barrel I! a turned portion having a uniform diameter which I mount in a sleeve I5 which may be exteriorly tapered throughout its length and having a bore corresponding to the turned portion of the barrel 55 and which is fitted with screw threads [6 dimensioned to engage the screw threads of the receiver it and be engaged therewith.

In this manner of construction and mounting the barrel of the fire arm is longitudinally movable and may have a floating action. The sleeve [5 is formed with slots l6 through which the sight blocks I! may be mounted. to the barrel and these slots closely approximate on their sides the width of the sight block but at the ends the slots are slightly longer than the sight blocks to permit of slight longitudinal and guided movement of the barrel in the sleeve. The barrel is held normally in a retracted position through the agency of a spring 29 acting against a screw pin it fitted to the barrel and passing through a slot 59 formed in the under side of the sleeve l5.

Engaging this pin and exerting rearward pressure I use a LI-shaped expansion spring 2!], one leg of which engages against the pin l8 and the other leg against the forward end of the slot l9. Through the agency of the spring and pin and of the barrel mounted for longitudinal movement in the sleeve l5, the rear of the barrel is held in retracted position under considerable pressure, the limit of rearward movement being determined by the placement of the pin in the barrel so that the pin engages against the rear of the slot l9.

When a cartridge is inserted in the barrel and the bolt 2i is set against the rim 22 of the cartridge 23 and the bolt is locked in firing position, the rim of the cartridge will be held tightly against the barrel under the pressure exerted by the spring 2 If the rim of the cartridge is of maximum thickness or greater than the minimum allowance, the barrel will give or be forced forward against the pressure of the spring 23 maintaining at all times a pressure on the cartridge rim and insuring uniformity of fire to increase accuracy to the greatest possible extent.

It is a well known fact among gun experts that cartridges, especially of the smaller caliber, rim fire type, vary greatly in the thickness of the rim and that some cartridges in present day firearms will fit loosely in the head space 24 between the end of the barrel and the bolt at the time of firing. This materially increases the inaccuracy in the result between one cartridge and another due to several causes, among which is that the dies that form the cartridge Wear and therefore do not deliver a uniform product. Another is that the gauge of the sheet metal from which the cartridges are formed will vary from one lot to another and also the sheets from which the cartridges will be formed will have a different gauge at the outside edge of the sheet than at the center, due to the spring in the rolls used in forming the sheet.

Due to these various causes a uniform cartridge is not possible but through the construction and features of my invention as applied to firearms it is possible to insure at all times that the rim of the cartridge will be firmly held between the end of,v the barrel the bolt. My construction provides an automatic head space take-up for shells or cartridge cases holding the rim firmly in place and experience has taught that greater accuracy of fire is attained through the use of the principle of my invention.

Practice has taught that an average rifie using standard ammunition, when accurately sighted upon a target, may be expected in a given number of shots to place the bullets within a certain area or circle on the target and that deviation at a given number of yards may be expected, as, for example, to be within a circle of four inches. Even the most expensive of target rifles made with the greatest precision by the best of experts will oftentimes show these erratic results.

In my experience using the principles of my invention incorporated into a standard rifle, I have found that I can very materially reduce the area over which a series of bullets will be placed. In fact, the accuracy is so great that the bullets may be placed directly on or within the area of the bulls-eye rather than over a wider area surrounding same. It has been found that oftentimes an unskilled person may outdo an expert when using a rifle or firearm involving the principles above described.

While I have described the operations of the principles of my invention in connection with a bolt action rifie or firearm of the small caliber type, it is to be understood that I am'not to be confined thereby to such specific firearm and that the principles may be applied to guns of larger caliber and of various kinds, including target pistols or such other arms as may be developed and that such principles may be applied to firearms utilizing the so-called rimless shells or other forms of ammunition when proper provision is made for engaging the shell so that the principles herein set forth may become opera tive thereon. It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size, and arrangement of parts may be resorted to and that various other expediences may be used in mounting the barrel and in insuring its operative movement without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a fire arm, a head space take-up comprising a sleeve secured in a receiver, a barrel mounted in the sleeve and having longitudinal movement therein, resilient means engaging the sleeve and the barrel for normally holding the barrel in retracted position to close the head space and permit forward movement of the barrel when under pressure.

2. In combination with a gun frame and its receiver, an automatic head space take-up for fire arms comprising a sleeve secured in the receiver, a slidably movable gun barrel mountedin the sleeve, means secured to the barrel and cooperating means therewith to normally hold the barrel in retracted position and close the head space, said barrel being yieldable under pressure from the shell and bolt.

3. In combination with a gun frame and its receiver on said frame, an automatic head space take-up for fire arms comprising a sleeve secured in the receiver, a gun barrel mounted in the sleeve for sliding movement therein, a pin fixed in the barrel and a spring cooperating therewith to normally hold the barrel in a retracted position and close the head space, said barrel being yieldable under pressure from the shell and bolt.

4. In combination with the gun frame and its receiver, an automatic head space take-up for fire arms comprising a sleeve secured in the receiver and the gun barrel mounted in the sleeve for sliding movement therein, sight lugs secured on said barrel extending through slots in the sleeve, said lugs cooperating with the sleeve to guide the barrel and prevent rotation thereof, a lug extending from the barrel and engaged by a spring to normally hold the barrel in retracted position, said spring allowing yielding of the barrel under pressure from the shell and bolt.

5. In combination with a gun frame and its receiver on said frame, an automatic head space take-up for fire arms comprising a sleeve secured in the receiver, a gun barrel mounted in the sleeve for sliding movement therein, a pin fixed the barrel and a substantially U-shaped spring cooperating therewith to normally hold the barrel in a retracted position and close. the head space, said barrel being yieldable under pressure from the shell and bolt.

6. In a fire arm, the combination with a receiver, a sleeve rigid therewith, a longitudinally movable barrel in said sleeve and adapted to receive a cartridge, and a bolt having a forward movement limit, of resilient means urging said barrel and cartridge into contact with said bolt, and means for limiting the longitudinal movement of said barrel when under pressure from said resilient means.

GEORGE EDWARD MUNSON. 

